Your objective in this challenge is to learn the regex syntax.
Regular Expressions are a powerful tool in your way to master programming, so you should be able to solve this challenge, at least!
The solution to every task is always the shortest regular expression pattern possible.
Also note that you have to submit delimiters in the patterns too. Example pattern: /joe/i. The delimiter has to be /

Your first lesson is easy: submit the regular expression the matches an empty string, and only an empty string.